Warning: IANAL.
Sanction here does not mean punishment, it means approved (the law itself says "upon request")
That article of the Criminal Code refers to two chapters of the Code of Criminal Procedure, which covers the two types of criminal investigations in France and their respective judicial authority: the prosecutor, and the judge of instruction (an investigative magistrate).
An order/request by the judge can be appealed against, I don't think the orders/requests of the prosecutor can be appealed.